/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
** Copyright (C) 2022 Rochus Keller (me@rochus-keller.ch) for LeanQt
**
** This file is part of the QtCore module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL21$
** GNU Lesser General Public License Usage
** This file may be used under the terms of the GNU Lesser
** General Public License version 2.1 or version 3 as published by the Free
** Software Foundation and appearing in the file LICENSE.LGPLv21 and
** LICENSE.LGPLv3 included in the packaging of this file. Please review the
** following information to ensure the GNU Lesser General Public License
** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** As a special exception, The Qt Company gives you certain additional
** rights. These rights are described in The Qt Company LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include "qthread.h"
#include "qthread_p.h"
#include "qthreadstorage.h"
#include "qmutex.h"

#include <qcoreapplication.h>
#include <qpointer.h>

#include <private/qcoreapplication_p.h>
#ifndef QT_NO_QOBJECT
#ifndef Q_OS_WINRT
#include <private/qeventdispatcher_win_p.h>
#else
#include <private/qeventdispatcher_winrt_p.h>
#endif
#endif

#include <qt_windows.h>

#ifndef Q_OS_WINRT
#ifndef Q_OS_WINCE
#ifndef _MT
#define _MT
#endif // _MT
#include <process.h>
#else   // !Q_OS_WINCE
#include "qfunctions_wince.h"
#endif // Q_OS_WINCE
#else // !Q_OS_WINRT
#endif // Q_OS_WINRT

#ifndef QT_NO_THREAD
QT_BEGIN_NAMESPACE

#ifdef Q_OS_WINRT
inline DWORD qWinRTTlsAlloc() {
    return FlsAlloc(0);
}

inline bool qWinRTTlsFree(DWORD dwTlsIndex) {
    return FlsFree(dwTlsIndex);
}

inline LPVOID qWinRTTlsGetValue(DWORD dwTlsIndex) {
    return FlsGetValue(dwTlsIndex);
}

inline bool qWinRTTlsSetValue(DWORD dwTlsIndex, LPVOID lpTlsValue) {
    return FlsSetValue(dwTlsIndex, lpTlsValue);
}

#define TlsAlloc qWinRTTlsAlloc
#define TlsFree qWinRTTlsFree
#define TlsSetValue qWinRTTlsSetValue
#define TlsGetValue qWinRTTlsGetValue

#endif // Q_OS_WINRT

void qt_watch_adopted_thread(const HANDLE adoptedThreadHandle, QThread *qthread);
DWORD WINAPI qt_adopted_thread_watcher_function(LPVOID);

static DWORD qt_current_thread_data_tls_index = TLS_OUT_OF_INDEXES;
void qt_create_tls()
{
    if (qt_current_thread_data_tls_index != TLS_OUT_OF_INDEXES)
        return;
    static QMutex mutex;
    QMutexLocker locker(&mutex);
    qt_current_thread_data_tls_index = TlsAlloc();
}

static void qt_free_tls()
{
    if (qt_current_thread_data_tls_index != TLS_OUT_OF_INDEXES) {
        TlsFree(qt_current_thread_data_tls_index);
        qt_current_thread_data_tls_index = TLS_OUT_OF_INDEXES;
    }
}
Q_DESTRUCTOR_FUNCTION(qt_free_tls)

/*
    QThreadData
*/
void QThreadData::clearCurrentThreadData()
{
    TlsSetValue(qt_current_thread_data_tls_index, 0);
}

QThreadData *QThreadData::current(bool createIfNecessary)
{
    qt_create_tls();
    QThreadData *threadData = reinterpret_cast<QThreadData *>(TlsGetValue(qt_current_thread_data_tls_index));
    if (!threadData && createIfNecessary) {
        threadData = new QThreadData;
        // This needs to be called prior to new AdoptedThread() to
        // avoid recursion.
        TlsSetValue(qt_current_thread_data_tls_index, threadData);
        QT_TRY {
            threadData->thread = new QAdoptedThread(threadData);
        } QT_CATCH(...) {
            TlsSetValue(qt_current_thread_data_tls_index, 0);
            threadData->deref();
            threadData = 0;
            QT_RETHROW;
        }
        threadData->deref();
        threadData->isAdopted = true;
        threadData->threadId = reinterpret_cast<Qt::HANDLE>(quintptr(GetCurrentThreadId()));

#ifndef QT_NO_COREAPPLICATION
        if (!QCoreApplicationPrivate::theMainThread) {
            QCoreApplicationPrivate::theMainThread = threadData->thread.load();
            // TODO: is there a way to reflect the branch's behavior using
            // WinRT API?
        } else 
#endif
		{
            HANDLE realHandle = INVALID_HANDLE_VALUE;
#if !defined(Q_OS_WINCE) || (defined(_WIN32_WCE) && (_WIN32_WCE>=0x600))
            DuplicateHandle(GetCurrentProcess(),
                    GetCurrentThread(),
                    GetCurrentProcess(),
                    &realHandle,
                    0,
                    FALSE,
                    DUPLICATE_SAME_ACCESS);
#else
                        realHandle = reinterpret_cast<HANDLE>(GetCurrentThreadId());
#endif
            qt_watch_adopted_thread(realHandle, threadData->thread);
        }
    }
    return threadData;
}

void QAdoptedThread::init()
{
    d_func()->handle = GetCurrentThread();
    d_func()->id = GetCurrentThreadId();
}

static QVector<HANDLE> qt_adopted_thread_handles;
static QVector<QThread *> qt_adopted_qthreads;
static QMutex qt_adopted_thread_watcher_mutex;
static DWORD qt_adopted_thread_watcher_id = 0;
static HANDLE qt_adopted_thread_wakeup = 0;

/*!
    \internal
    Adds an adopted thread to the list of threads that Qt watches to make sure
    the thread data is properly cleaned up. This function starts the watcher
    thread if necessary.
*/
void qt_watch_adopted_thread(const HANDLE adoptedThreadHandle, QThread *qthread)
{
    QMutexLocker lock(&qt_adopted_thread_watcher_mutex);

    if (GetCurrentThreadId() == qt_adopted_thread_watcher_id) {
#if !defined(Q_OS_WINCE) || (defined(_WIN32_WCE) && (_WIN32_WCE>=0x600))
        CloseHandle(adoptedThreadHandle);
#endif
        return;
    }

    qt_adopted_thread_handles.append(adoptedThreadHandle);
    qt_adopted_qthreads.append(qthread);

    // Start watcher thread if it is not already running.
    if (qt_adopted_thread_watcher_id == 0) {
        if (qt_adopted_thread_wakeup == 0) {
#ifndef Q_OS_WINRT
            qt_adopted_thread_wakeup = CreateEvent(0, false, false, 0);
#else
            qt_adopted_thread_wakeup = CreateEventEx(0, NULL, 0, EVENT_ALL_ACCESS);
#endif
            qt_adopted_thread_handles.prepend(qt_adopted_thread_wakeup);
        }

        CloseHandle(CreateThread(0, 0, qt_adopted_thread_watcher_function, 0, 0, &qt_adopted_thread_watcher_id));
    } else {
        SetEvent(qt_adopted_thread_wakeup);
    }
}

/*
    This function loops and waits for native adopted threads to finish.
    When this happens it derefs the QThreadData for the adopted thread
    to make sure it gets cleaned up properly.
*/
DWORD WINAPI qt_adopted_thread_watcher_function(LPVOID)
{
    forever {
        qt_adopted_thread_watcher_mutex.lock();

        if (qt_adopted_thread_handles.count() == 1) {
            qt_adopted_thread_watcher_id = 0;
            qt_adopted_thread_watcher_mutex.unlock();
            break;
        }

        QVector<HANDLE> handlesCopy = qt_adopted_thread_handles;
        qt_adopted_thread_watcher_mutex.unlock();

        DWORD ret = WAIT_TIMEOUT;
        int count;
        int offset;
        int loops = handlesCopy.size() / MAXIMUM_WAIT_OBJECTS;
        if (handlesCopy.size() % MAXIMUM_WAIT_OBJECTS)
            ++loops;
        if (loops == 1) {
            // no need to loop, no timeout
            offset = 0;
            count = handlesCopy.count();
#ifndef Q_OS_WINRT
            ret = WaitForMultipleObjects(handlesCopy.count(), handlesCopy.constData(), false, INFINITE);
#else
            ret = WaitForMultipleObjectsEx(handlesCopy.count(), handlesCopy.constData(), false, INFINITE, false);
#endif
        } else {
            int loop = 0;
            do {
                offset = loop * MAXIMUM_WAIT_OBJECTS;
                count = qMin(handlesCopy.count() - offset, MAXIMUM_WAIT_OBJECTS);
#ifndef Q_OS_WINRT
                ret = WaitForMultipleObjects(count, handlesCopy.constData() + offset, false, 100);
#else
                ret = WaitForMultipleObjectsEx(count, handlesCopy.constData() + offset, false, 100, false);
#endif
                loop = (loop + 1) % loops;
            } while (ret == WAIT_TIMEOUT);
        }

        if (ret == WAIT_FAILED || ret >= WAIT_OBJECT_0 + uint(count)) {
            qWarning("QThread internal error while waiting for adopted threads: %d", int(GetLastError()));
            continue;
        }

        const int handleIndex = offset + ret - WAIT_OBJECT_0;
        if (handleIndex == 0){
            // New handle to watch was added.
            continue;
        } else {
//             printf("(qt) - qt_adopted_thread_watcher_function... called\n");
            const int qthreadIndex = handleIndex - 1;

            qt_adopted_thread_watcher_mutex.lock();
            QThreadData *data = QThreadData::get2(qt_adopted_qthreads.at(qthreadIndex));
            qt_adopted_thread_watcher_mutex.unlock();
            if (data->isAdopted) {
                QThread *thread = data->thread;
                Q_ASSERT(thread);
                QThreadPrivate *thread_p = static_cast<QThreadPrivate *>(QObjectPrivate::get(thread));
                Q_UNUSED(thread_p)
                Q_ASSERT(!thread_p->finished);
                thread_p->finish(thread);
            }
            data->deref();

            QMutexLocker lock(&qt_adopted_thread_watcher_mutex);
#if !defined(Q_OS_WINCE) || (defined(_WIN32_WCE) && (_WIN32_WCE>=0x600))
            CloseHandle(qt_adopted_thread_handles.at(handleIndex));
#endif
            qt_adopted_thread_handles.remove(handleIndex);
            qt_adopted_qthreads.remove(qthreadIndex);
        }
    }

    QThreadData *threadData = reinterpret_cast<QThreadData *>(TlsGetValue(qt_current_thread_data_tls_index));
    if (threadData)
        threadData->deref();

    return 0;
}

#if !defined(QT_NO_DEBUG) && defined(Q_CC_MSVC) && !defined(Q_OS_WINCE) && !defined(Q_OS_WINRT)

#ifndef Q_OS_WIN64
#  define ULONG_PTR DWORD
#endif

typedef struct tagTHREADNAME_INFO
{
    DWORD dwType;      // must be 0x1000
    LPCSTR szName;     // pointer to name (in user addr space)
    HANDLE dwThreadID; // thread ID (-1=caller thread)
    DWORD dwFlags;     // reserved for future use, must be zero
} THREADNAME_INFO;

void qt_set_thread_name(HANDLE threadId, LPCSTR threadName)
{
    THREADNAME_INFO info;
    info.dwType = 0x1000;
    info.szName = threadName;
    info.dwThreadID = threadId;
    info.dwFlags = 0;

    __try
    {
        RaiseException(0x406D1388, 0, sizeof(info)/sizeof(DWORD), (const ULONG_PTR*)&info);
    }
    __except (EXCEPTION_CONTINUE_EXECUTION)
    {
    }
}
#endif // !QT_NO_DEBUG && Q_CC_MSVC && !Q_OS_WINCE && !Q_OS_WINRT

/**************************************************************************
 ** QThreadPrivate
 *************************************************************************/

#endif // QT_NO_THREAD

void QThreadPrivate::createEventDispatcher(QThreadData *data)
{
#ifndef QT_NO_QOBJECT
#ifndef Q_OS_WINRT
    QEventDispatcherWin32 *theEventDispatcher = new QEventDispatcherWin32;
#else
    QEventDispatcherWinRT *theEventDispatcher = new QEventDispatcherWinRT;
#endif
    data->eventDispatcher.storeRelease(theEventDispatcher);
    theEventDispatcher->startingUp();
#endif
}

#ifndef QT_NO_THREAD

unsigned int __stdcall QT_ENSURE_STACK_ALIGNED_FOR_SSE QThreadPrivate::start(void *arg)
{
    QThread *thr = reinterpret_cast<QThread *>(arg);
    QThreadData *data = QThreadData::get2(thr);

    qt_create_tls();
    TlsSetValue(qt_current_thread_data_tls_index, data);
    data->threadId = reinterpret_cast<Qt::HANDLE>(quintptr(GetCurrentThreadId()));

    QThread::setTerminationEnabled(false);

    {
        QMutexLocker locker(&thr->d_func()->mutex);
        data->quitNow = thr->d_func()->exited;
    }

#ifndef QT_NO_QOBJECT
    if (data->eventDispatcher.load()) // custom event dispatcher set?
        data->eventDispatcher.load()->startingUp();
    else
        createEventDispatcher(data);
#endif

#if !defined(QT_NO_DEBUG) && defined(Q_CC_MSVC) && !defined(Q_OS_WINCE) && !defined(Q_OS_WINRT)
    // sets the name of the current thread.
    QByteArray objectName = thr->objectName().toLocal8Bit();
#ifndef QT_NO_QOBJECT
	if( objectName.isEmpty() )
		qt_set_thread_name((HANDLE)-1, thr->metaObject()->className());
	else
#endif
		qt_set_thread_name((HANDLE)-1,objectName.constData());
#endif

#ifndef QT_NO_QOBJECT
    emit thr->started(QThread::QPrivateSignal());
#endif
    QThread::setTerminationEnabled(true);
    thr->run();

    finish(arg);
    return 0;
}

void QThreadPrivate::finish(void *arg, bool lockAnyway)
{
    QThread *thr = reinterpret_cast<QThread *>(arg);
    QThreadPrivate *d = thr->d_func();

    QMutexLocker locker(lockAnyway ? &d->mutex : 0);
    d->isInFinish = true;
    d->priority = QThread::InheritPriority;
    void **tls_data = reinterpret_cast<void **>(&d->data->tls);
    locker.unlock();
#ifndef QT_NO_QOBJECT
    emit thr->finished(QThread::QPrivateSignal());
#endif
#if !defined(QT_NO_QOBJECT) && !defined(QT_NO_COREAPPLICATION)
    QCoreApplication::sendPostedEvents(0, QEvent::DeferredDelete);
#endif
    QThreadStorageData::finish(tls_data);
    locker.relock();

#ifndef QT_NO_QOBJECT
    QAbstractEventDispatcher *eventDispatcher = d->data->eventDispatcher.load();
    if (eventDispatcher) {
        d->data->eventDispatcher = 0;
        locker.unlock();
        eventDispatcher->closingDown();
        delete eventDispatcher;
        locker.relock();
    }
#endif

    d->running = false;
    d->finished = true;
    d->isInFinish = false;
    d->interruptionRequested = false;

    if (!d->waiters) {
        CloseHandle(d->handle);
        d->handle = 0;
    }

    d->id = 0;
}

/**************************************************************************
 ** QThread
 *************************************************************************/

Qt::HANDLE QThread::currentThreadId() Q_DECL_NOTHROW
{
    return reinterpret_cast<Qt::HANDLE>(quintptr(GetCurrentThreadId()));
}

int QThread::idealThreadCount() Q_DECL_NOTHROW
{
    SYSTEM_INFO sysinfo;
#ifndef Q_OS_WINRT
    GetSystemInfo(&sysinfo);
#else
    GetNativeSystemInfo(&sysinfo);
#endif
    return sysinfo.dwNumberOfProcessors;
}

void QThread::yieldCurrentThread()
{
#if !defined(Q_OS_WINCE) && !defined(Q_OS_WINRT)
    SwitchToThread();
#else
    ::Sleep(0);
#endif
}

void QThread::sleep(unsigned long secs)
{
    ::Sleep(secs * 1000);
}

void QThread::msleep(unsigned long msecs)
{
    ::Sleep(msecs);
}

void QThread::usleep(unsigned long usecs)
{
    ::Sleep((usecs / 1000) + 1);
}

void QThread::start(Priority priority)
{
    Q_D(QThread);
    QMutexLocker locker(&d->mutex);

    if (d->isInFinish) {
        locker.unlock();
        wait();
        locker.relock();
    }

    if (d->running)
        return;

    d->running = true;
    d->finished = false;
    d->exited = false;
    d->returnCode = 0;
    d->interruptionRequested = false;

#ifndef Q_OS_WINRT
    /*
      NOTE: we create the thread in the suspended state, set the
      priority and then resume the thread.

      since threads are created with normal priority by default, we
      could get into a case where a thread (with priority less than
      NormalPriority) tries to create a new thread (also with priority
      less than NormalPriority), but the newly created thread preempts
      its 'parent' and runs at normal priority.
    */
    d->handle = (Qt::HANDLE) _beginthreadex(NULL, d->stackSize, QThreadPrivate::start,
                                            this, CREATE_SUSPENDED, &(d->id));
#else // !Q_OS_WINRT
    d->handle = (Qt::HANDLE) CreateThread(NULL, d->stackSize, (LPTHREAD_START_ROUTINE)QThreadPrivate::start,
                                            this, CREATE_SUSPENDED, reinterpret_cast<LPDWORD>(&d->id));
#endif // Q_OS_WINRT

    if (!d->handle) {
        qErrnoWarning(errno, "QThread::start: Failed to create thread");
        d->running = false;
        d->finished = true;
        return;
    }

    int prio;
    d->priority = priority;
    switch (d->priority) {
    case IdlePriority:
        prio = THREAD_PRIORITY_IDLE;
        break;

    case LowestPriority:
        prio = THREAD_PRIORITY_LOWEST;
        break;

    case LowPriority:
        prio = THREAD_PRIORITY_BELOW_NORMAL;
        break;

    case NormalPriority:
        prio = THREAD_PRIORITY_NORMAL;
        break;

    case HighPriority:
        prio = THREAD_PRIORITY_ABOVE_NORMAL;
        break;

    case HighestPriority:
        prio = THREAD_PRIORITY_HIGHEST;
        break;

    case TimeCriticalPriority:
        prio = THREAD_PRIORITY_TIME_CRITICAL;
        break;

    case InheritPriority:
    default:
        prio = GetThreadPriority(GetCurrentThread());
        break;
    }

    if (!SetThreadPriority(d->handle, prio)) {
        qErrnoWarning("QThread::start: Failed to set thread priority");
    }

    if (ResumeThread(d->handle) == (DWORD) -1) {
        qErrnoWarning("QThread::start: Failed to resume new thread");
    }
}

void QThread::terminate()
{
    Q_D(QThread);
    QMutexLocker locker(&d->mutex);
    if (!d->running)
        return;
    if (!d->terminationEnabled) {
        d->terminatePending = true;
        return;
    }

    // Calling ExitThread() in setTerminationEnabled is all we can do on WinRT
#ifndef Q_OS_WINRT
    TerminateThread(d->handle, 0);
#endif
    QThreadPrivate::finish(this, false);
}

bool QThread::wait(unsigned long time)
{
    Q_D(QThread);
    QMutexLocker locker(&d->mutex);

    if (d->id == GetCurrentThreadId()) {
        qWarning("QThread::wait: Thread tried to wait on itself");
        return false;
    }
    if (d->finished || !d->running)
        return true;

    ++d->waiters;
    locker.mutex()->unlock();

    bool ret = false;
#ifndef Q_OS_WINRT
    switch (WaitForSingleObject(d->handle, time)) {
#else
    switch (WaitForSingleObjectEx(d->handle, time, false)) {
#endif
    case WAIT_OBJECT_0:
        ret = true;
        break;
    case WAIT_FAILED:
        qErrnoWarning("QThread::wait: Thread wait failure");
        break;
    case WAIT_ABANDONED:
    case WAIT_TIMEOUT:
    default:
        break;
    }

    locker.mutex()->lock();
    --d->waiters;

    if (ret && !d->finished) {
        // thread was terminated by someone else

        QThreadPrivate::finish(this, false);
    }

    if (d->finished && !d->waiters) {
        CloseHandle(d->handle);
        d->handle = 0;
    }

    return ret;
}

void QThread::setTerminationEnabled(bool enabled)
{
    QThread *thr = currentThread();
    Q_ASSERT_X(thr != 0, "QThread::setTerminationEnabled()",
               "Current thread was not started with QThread.");
    QThreadPrivate *d = thr->d_func();
    QMutexLocker locker(&d->mutex);
    d->terminationEnabled = enabled;
    if (enabled && d->terminatePending) {
        QThreadPrivate::finish(thr, false);
        locker.unlock(); // don't leave the mutex locked!
#ifndef Q_OS_WINRT
        _endthreadex(0);
#else
        ExitThread(0);
#endif
    }
}

// Caller must hold the mutex
void QThreadPrivate::setPriority(QThread::Priority threadPriority)
{
    // copied from start() with a few modifications:

    int prio;
    priority = threadPriority;
    switch (priority) {
    case QThread::IdlePriority:
        prio = THREAD_PRIORITY_IDLE;
        break;

    case QThread::LowestPriority:
        prio = THREAD_PRIORITY_LOWEST;
        break;

    case QThread::LowPriority:
        prio = THREAD_PRIORITY_BELOW_NORMAL;
        break;

    case QThread::NormalPriority:
        prio = THREAD_PRIORITY_NORMAL;
        break;

    case QThread::HighPriority:
        prio = THREAD_PRIORITY_ABOVE_NORMAL;
        break;

    case QThread::HighestPriority:
        prio = THREAD_PRIORITY_HIGHEST;
        break;

    case QThread::TimeCriticalPriority:
        prio = THREAD_PRIORITY_TIME_CRITICAL;
        break;

    case QThread::InheritPriority:
    default:
        qWarning("QThread::setPriority: Argument cannot be InheritPriority");
        return;
    }

    if (!SetThreadPriority(handle, prio)) {
        qErrnoWarning("QThread::setPriority: Failed to set thread priority");
    }
}

QT_END_NAMESPACE
#endif // QT_NO_THREAD
